Supporters of decriminalizing marijuana are hoping to build momentum on Capitol Hill after a historic election that saw the politics of pot take center stage in four states.

The marijuana industry's public relations campaign has so far been limited to states, especially California, where a ballot initiative to legalize weed failed in November.

But today, the National Cannabis Industry Association, launched in December to represent the interests of legal marijuana growers and distributors, will hold the first congressional lobbying day in the nation's capital, hoping to shore up support for an industry they say could bring billions of dollars in revenue to the government.

The industry already has some notable lawmakers on its side.

Rep. Barney Frank, D-Mass., has in the past introduced legislation to remove federal penalties for personal use of marijuana. Libertarian-leaning Rep. Ron Paul, R-Texas, is also an outspoken advocate of full marijuana legalization.

Last summer, Frank and 15 other lawmakers sent a letter to Treasury Secretary Tim Geithner asking his agency to set rules that provide financial services to medical marijuana dispensaries and to assure banks they won't be penalized for conducting such business.

Today's lobbying efforts will focus on eliminating such restrictions and on easing the tax burden on medical marijuana clinics.

Supporters of decriminalizing marijuana say it will help the United States in the long term by boosting profits for the government. Socially, they say it will boost resources to crack down on hard drugs and will curb teen marijuana use, which is on the rise.

"Regulation will absolutely succeed in keeping it out of the hands of kids more effectively than prohibition because prohibition has created a large underground market," Rep. Jared Polis, D-Colo., told ABC News. "If you legalize it just like we have with alcohol, you will have a much better control.

"It would really provide America with a leg up on the drug war by preventing the marijuana engine that fuels the coffers of the [Mexican drug] cartels," he said. "You have more resources to crack down on hard drugs."

Others also tout its economic benefits.

According to a recent report by an analyst firm See Change Strategy, the national market for medical marijuana is worth $1.7 billion in 2011 and could reach $8.9 billion in five years. The black market, the report stated, is estimated at $18 billion.

Forty-six percent of Americans support legalizing marijuana, a new high, according to a survey conducted by Gallup in October. The trend has shifted upward in recent decades while opposition to such a move has declined.

For medical marijuana use, the support is even higher. Seventy percent of Americans said they favored making marijuana for medicinal purposes legally available.

"It's going to take a number of years to reach a point when there's a broad consensus that marijuana prohibition should end but it will come," said Steve Fox, NCIA's director of public affairs. "When you look at the demographics in terms of polling, it's clear that the older generations are opposed to the legal cannabis market, but the younger generations are more strongly in favor. It's really just a matter of time before support outweighs the opposition."

But as proponents admit, it could be some time before lawmakers are high on the idea of loosening up federal standards for marijuana.

Polis says there are informal discussions among his peers and a possible bill liberalizing marijuana laws gains more support in every session, but it could be several more sessions before legislation is passed.

Even in states with liberal marijuana laws, full legalization has yet to gain steam. Proposition 19 in California failed in November despite heavy lobbying. In early 2010, the Washington state legislature struck down a marijuana-legalization bill that was introduced in Washington.

Medical marijuana is currently legal in 15 states and Washington, D.C.